[FFmpeg-trac] #11314(avdevice:new): "alsa" + "v4l2" capturing had audio stuttering with "-c:a copy"

[FFmpeg]

#11314: "alsa" + "v4l2" capturing had audio stuttering with "-c:a copy"
-----------------------------------+------------------------------------
             Reporter:  chconnor   |                    Owner:  (none)
                 Type:  defect     |                   Status:  new
             Priority:  normal     |                Component:  avdevice
              Version:  7.0        |               Resolution:
             Keywords:  alsa v4l2  |               Blocked By:
             Blocking:             |  Reproduced by developer:  0
Analyzed by developer:  1          |
-----------------------------------+------------------------------------
Comment (by chconnor):

 Capturing with only -c:a pcms16le:

 {{{
 ffmpeg -report -f alsa -ac 2 -i hw:CARD=Cx231xxAudio,DEV=0 -f v4l2 -i
 /dev/video2 -c:a pcm_s16le -c:v rawvideo test-pcms16le.avi
 }}}

 ...generates a working file (with same "non-monotonic" errors).

 Capturing with only -ar:

 {{{
 ffmpeg -report -f alsa -ac 2 -i hw:CARD=Cx231xxAudio,DEV=0 -f v4l2 -i
 /dev/video2 -ar 48000 -c:v rawvideo test-ar.avi
 }}}

 ...generates a working file (with same "non-monotonic" errors). But the
 resulting audio stream is mp3 (mp3 (mp3float) (U[0][0][0] / 0x0055), 48000
 Hz, stereo, fltp, 128 kb/s), and during capture there are additional
 errors like this:

 [libmp3lame @ 0x61fc116cd800] Queue input is backward in time

 Capturing only audio:

 {{{
 ffmpeg -report -f alsa -ac 2 -i hw:CARD=Cx231xxAudio,DEV=0 -c:a copy
 test.wav
 }}}

 ...generates a working .wav file (with same "non-monotonic" errors).

 Let me know if you'd like logs or ashowinfo from any of those tests.
-- 
Ticket URL: <https://trac.ffmpeg.org/ticket/11314#comment:4>
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